Significant improvements in animal performance, efficiency and carcass and meat quality have been made over the years through the application of standard animal breeding and selection techniques. However, such classical animal breeding techniques require several years of genetic evaluation of performance records on individual animals and their relatives and are therefore very expensive. Other efforts have been made to improve productivity and quality through the application of such management practices as the use of feed additives, animal hormonal implants and chemotherapeutics. However, there is significant political and regulatory resistance to the introduction and use of such methodologies. Such methodologies are also non-inheritable and need to be applied differently in every production system.
There is a need for methods that allow relatively easy and more efficient selection and breeding of farm animals with an advantage for an inheritable trait of circulating leptin levels, feed intake, growth rate, body weight, carcass merit and carcass composition. The economic significance of the use of genetic markers that are associated with specific economically important traits (especially traits with low heritability) in livestock through marker-assisted selection cannot therefore be over-emphasized.
The physiological regulation of intake, growth and energy partitioning in animals is under the control of multiple genes, which may be important candidates for unraveling the genetic variation in economically relevant traits (ERT) in beef production. Polymorphisms in these candidate genes that show association with specific ERT are useful quantitative trait nucleotides for marker-assisted selection. In the present study, associations between single nucleotide polymorphisms (SNPs) in the fatty acid binding protein 4 (“FABP4”) gene with marbling and subcutaneous fat depth have been found.
Fatty acid binding proteins are a family of small, highly conserved, cytoplasmic proteins that bind long-chain fatty acids and other hydrophobic ligands (Kaikaus et al. 1990. Experientia, 46: 617-630). Their major functions include fatty acid uptake, transport, and metabolism. So far, nine distinct members have been identified in this gene family (Damcott et al. 2004. Metabolism, 53: 303-309), including adipocyte fatty acid binding protein or fatty acid binding protein 4 (“FABP4”). FABP4 plays a major role in the regulation of lipid and glucose homeostasis through its interaction with perioxisome proliferator-activated receptors (PPARs), located in the cell nucleus Specifically; the FABP4/fatty acid complex activates the PPAR-γ isoform, which in turn, regulates transcription of FABP4 (Damcott et al. 2004. Metabolism, 53: 303-309). In addition, FABP4 appears to be involved in lipid hydrolysis and intracellular fatty acid trafficking through direct interaction and binding to hormone-sensitive lipase (Shen et al. 1999. Proc Natl Acad Sci U S A, 96: 5528-5532), which is a primary enzyme involved in lipid catabolism (Tansey et al. 2003. J Biol Chem. 278: 8401-8406). Recently, FABP4 and FABP5 were proposed as potential candidate genes for obesity as they are located within a quantitative trait loci (QTL) region for serum leptin levels in mice (Ogino et al. 2003. Mamm Genome, 14: 839-844). Leptin, a 16-kDa protein secreted from white adipocytes, is involved in the regulation of food intake, energy expenditure, and whole-body energy balance (Jiang and Gibson 1999. Mamm Genome, 10: 191-193). All these factors indicate that FABP4 may play an important role in lipid metabolism and homeostasis in adipocytes.
It remains advantageous to provide further SNPs that may more accurately predict the meat quality phenotype of an animal and also a business method that provides for increased production efficiencies in livestock cattle, as well as providing access to various records of the animals and allows comparisons with expected or desired goals with regard to the quality and quantity of animals produced.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.